Field replaceable packaged refrigeration module with thermosyphon for cooling electronic components

ABSTRACT

A field and/or customer replaceable packaged refrigeration module with thermosyphon is suitable for use in standard electronic component environments. The field replaceable packaged refrigeration module portion is self-contained and is specifically designed to have physical dimensions similar to those of a standard air-based cooling system, such as a fined heat sink or heat pipe. The field replaceable packaged refrigeration module is coupled to a thermosyphon and serves to lower the base temperature of the thermosyphon sub-system, thereby allowing intermittent operation of the field replaceable packaged refrigeration module with the thermosyphon sub-system.

FIELD OF THE INVENTION

[0001] The present invention relates to a refrigeration system forcooling electrical components. More particularly, the invention relatesto a field and/or customer replaceable refrigeration module coupled to athermosyphon that is suitable for use in standard electronic componentenvironments.

BACKGROUND OF THE INVENTION

[0002] Electronic components, such as microprocessors and other variousintegrated circuits, have advanced in at least two significant ways.First, feature sizes have moved into the sub-micron range therebyallowing larger numbers of transistors to be formed on a given surfacearea. This in turn has resulted in greater device and circuit density onthe individual chips. Second, in part due to the first advance discussedabove, microprocessors have increased dramatically in clock speed. Atpresent microprocessor speeds of 2.5 Gigahertz are coming to market andthe 3 and 4 Gigahertz range is rapidly being approached.

[0003] As a result of the advances in device density and microprocessorspeed discussed above, heat dissipation, which has always been a problemin the past, is rapidly becoming the limiting factor in microprocessorperformance. Consequently, heat dissipation and cooling is now theforemost concern and the major obstacle faced by system designers.

[0004] As noted, heat dissipation has long been recognized as a seriousproblem limiting the performance of electronic components and systems.In the past, the solutions to the heat dissipation problem have beenmostly limited to air-based cooling systems, with only the most exoticmilitary, scientific and custom electronic systems employing the bulkyand costly prior art liquid-based cooling solutions.

[0005] In the prior art, air-based cooling systems, such as heat sinks,cooling fins, heat pipes and fans, have been the systems of choice forseveral reasons. First, the air-based cooling systems of the prior artwere modular and self-contained and were therefore field replaceablewith minimal effort using standard tools. Second, the prior artair-based cooling systems attached directly to the components thatneeded cooling and a discrete cooling unit could be provided for eachheat source. In addition, air-based cooling systems were compact andsimple in both operation and installation, with minimal parts to fail orbreak and minimal added system complexity. Therefore, prior artair-based cooling systems were reliable. In addition, and probably mostimportantly, in the prior art, air-based cooling systems couldreasonably meet the cooling needs of electronic devices and systems sothere was little motivation to move to the more complex and problematicliquid-based systems. However, as noted above, due to the advances inmicroprocessor speeds and device density, air-based cooling systemsalone will most likely not be a viable option for electronic devicecooling for the next generation of microprocessors.

[0006] As noted above, another possible prior art cooling system thatcould potentially provide the level of cooling required by the nextgeneration of microprocessors is liquid-based cooling systems. Prior artliquid-based cooling systems typically used a refrigerant, such asR134A, that was circulated by a compressor. In prior art liquid-basedcooling systems the compressor was typically a crankshaft reciprocatingcompressor or a rotary compressor similar to those used in homerefrigerators.

[0007] As noted above, prior art liquid-based cooling systems have farmore potential cooling capability than air-based systems. However, inthe prior art liquid-based cooling systems, the crankshaft reciprocatingor rotary compressors were typically, by electronics industry standards,very large, on the order of tens of inches in diameter, very heavy, onthe order of pounds, and often required more power to operate than theentire electronic system they would be charged with cooling. Inaddition, the size and design of prior art liquid-based cooling systemsoften required that the major components of the prior art liquid-basedcooling system be centrally located, typically remote from theelectronic devices to be cooled, and that a complicated system of tubingor “plumbing” be used to bring the cooling liquid into thermal contactwith the heat source, i.e., with the microprocessor or other integratedcircuit. Consequently, unlike prior art air-based cooling systems, priorart liquid-based cooling systems were not modular, were notself-contained, and often required special expertise and tools formaintenance and operation. In addition, unlike the prior art air-basedcooling systems discussed above, prior art liquid-based cooling systemsdid not attach directly to the components that needed cooling and adiscrete cooling unit typically could not be provided for each heatsource. Also, unlike the prior art air-based cooling systems discussedabove, prior art liquid-based cooling systems were not compact and werenot simple in either operation or installation. Indeed, prior artliquid-based cooling systems typically included numerous parts whichcould potentially fail or break. This added complexity, and threat ofcomponent failure, was particularly problematic with respect to theassociated plumbing discussed above because a failure of any of thetubes could result in the introduction of liquid refrigerant into, oronto, the electronic devices and could cause catastrophic systemfailure.

[0008] In addition, prior art liquid-based cooling systems employedcompressors that typically were highly orientation dependent, i.e., theycould not operate at angles of more than 30 or 40 degrees. Consequently,prior art liquid based cooling systems were particularly ill suited forthe electronics industry that stresses flexibility and often requiresorientation independent operation.

[0009] Given that, as discussed above, air-based cooling systems havereached their operational limits when it comes to cooling electroniccomponents, there is a growing realization that some other form ofcooling system, such as liquid-based cooling systems will need to beadopted by the electronics industry. However, as discussed above, priorart liquid-based cooling systems are far from ideal and, thus far, theindustry has not adopted liquid-based cooling in any meaningful waybecause the problems associated with prior art liquid-based coolingsystems are still thought to outweigh the advantages these systemsprovide in terms of increased cooling capacity.

[0010] What is needed is a cooling system that has the cooling capacityand efficiency of a liquid-based cooling system yet has the advantagesof being modular, simple, and compact like air-based cooling systems.

SUMMARY OF THE INVENTION

[0011] The present invention is directed to a field and/or customerreplaceable packaged refrigeration module with thermosyphon that issuitable for use in standard electronic component environments.According to the present invention, advances in compressor technologyare incorporated in a field replaceable packaged refrigeration modulethat is coupled to a thermosyphon cold plate evaporator to be used forcooling electronic components. According to the invention, the fieldreplaceable packaged refrigeration module is self-contained and isspecifically designed to have physical dimensions similar to those of astandard air-based cooling system, such as a fined heat sink or heatpipe.

[0012] In one embodiment of the invention, the addition of the fieldreplaceable packaged refrigeration module to a thermosyphon serves tocreate a system wherein the thermosyphon is used to passively cool theheat source and the field replaceable packaged refrigeration module isused to lower, or maintain, the base temperature of the thermosyphon.Consequently, the field replaceable packaged refrigeration module can beoperated intermittently, on an as needed basis, to minimize the powerused by the system and to minimize the wear and tear of the movingparts. The net result is the ability to manage and remove heat from theheat source while saving energy since the field replaceable packagedrefrigeration module does not need to operate at all times.Consequently, the use of a thermosyphon with the field replaceablepackaged refrigeration module allows for more cooling capability andmore efficient cooling, lowered load on the field replaceable packagedrefrigeration module, and a lower failure rate of the cooling system andits moving parts.

[0013] The present invention can be utilized in existing electronicsystems and unlike prior art liquid-based cooling systems, the variousparts of the field replaceable packaged refrigeration module withthermosyphon of the invention, including the very minimal tubing, arelargely self-contained in the field replaceable packaged refrigerationmodule with thermosyphon. Therefore a failure of any of the tubes wouldtypically not result in the introduction of liquid into, or onto, theelectronic devices and would not cause catastrophic system failure, aswas the risk with prior art liquid-based cooling systems.

[0014] The field replaceable packaged refrigeration module withthermosyphon of the present invention is a modified liquid-based coolingsystem and therefore provides the cooling capacity of a prior artliquid-based cooling systems. However, unlike prior art liquid-basedcooling systems, the field replaceable packaged refrigeration modulewith thermosyphon of the invention is modular and largely self-containedand is therefore field and/or customer replaceable with minimal effortusing standard tools. In addition, unlike prior art liquid-based coolingsystem, the field replaceable packaged refrigeration module withthermosyphon of the invention, in one embodiment, uses the passive,simple and low energy thermosyphon to perform the majority of theroutine cooling, while providing the added cooling capacity of aliquid-based cooling system in the form of the intermittently operatingfield replaceable packaged refrigeration module. In another embodiment,the field replaceable packaged refrigeration module is positioneddirectly over the main heat source, such as a CPU, while thethermosyphon is used for smaller heat sources or secondary cooling. Inaddition, unlike prior art liquid-based cooling systems, the fieldreplaceable packaged refrigeration module with thermosyphon of theinvention is compact and simple in both operation and installation, withminimal parts to fail or break and minimal added complexity. Therefore,unlike prior art liquid-based cooling systems, the field replaceablepackaged refrigeration module with thermosyphon of the invention issturdy and reliable.

[0015] In one embodiment of the invention, a single thermosyphon iscoupled to a single field replaceable packaged refrigeration module as aunit. In other embodiments of the invention, multiple thermosyphons arecoupled to, and serviced by, a single field replaceable packagedrefrigeration module mounted in a central location. In this way, singleor multiple heat sources can be serviced by a single field replaceablepackaged refrigeration module.

[0016] In addition, the field replaceable packaged refrigeration moduleportion of the present invention is specifically designed to beoperational in any orientation. Consequently, unlike prior artliquid-based cooling systems, the field replaceable packagedrefrigeration module portion of the present invention can be mounted,and operated, at any angle. This makes the field replaceable packagedrefrigeration module with thermosyphon of the present inventionparticularly well suited for use with electronic systems.

[0017] As discussed briefly above, and in more detail below, the fieldreplaceable packaged refrigeration module with thermosyphon of thepresent invention has the cooling capacity of a liquid-based coolingsystem and yet is modular, compact, simple in design and simple to use,like an air-based cooling system. Consequently, the field replaceablepackaged refrigeration module with thermosyphon of the present inventioncan readily meet the cooling needs of the next generation of electronicdevices and systems. As one example, when the field replaceable packagedrefrigeration module with thermosyphon of the present invention is usedto cool a microprocessor or CPU, the CPU can operate at a higherfrequency and speed, thereby allowing the parent electronic system tofully utilize the advances in microprocessor technology discussed above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The refrigeration system of the present invention will bedescribed in the following detailed description, with reference to theaccompanying drawings. In the drawings, the same reference numbers areused to denote similar components in the various embodiments.

[0019]FIG. 1 is a functional diagram of a field replaceable packagedrefrigeration module designed according to the principles of oneembodiment of the invention;

[0020]FIG. 2 is a longitudinal cross sectional view of an exemplarylinear compressor that may be used in the field replaceable packagedrefrigeration module depicted in FIG. 1 according to the principles ofone embodiment of the invention;

[0021]FIG. 3 is a perspective view of a field replaceable packagedrefrigeration module designed according to the principles of oneembodiment of the invention;

[0022]FIG. 4 is cross sectional view of the field replaceable packagedrefrigeration module of FIG. 3 shown mounted on an exemplary electricalcomponent according to the principles of one embodiment of theinvention;

[0023]FIG. 5 is a computer-generated representation of one embodiment ofthe field replaceable packaged refrigeration module of FIG. 3 accordingto the principles of one embodiment of the invention.

[0024]FIG. 6 is cross sectional view of one embodiment of a fieldreplaceable packaged refrigeration module with thermosyphon according tothe principles of the present invention.

DETAILED DESCRIPTION

[0025] The field replaceable packaged refrigeration module withthermosyphon (600 in FIG. 6) of the present invention has theadvantageous cooling capacity of a prior art liquid-based coolingsystem, yet, unlike prior art liquid-based cooling systems, the fieldreplaceable packaged refrigeration module with thermosyphon of thepresent invention is suitable for use in standard electronic componentenvironments.

[0026] In one embodiment of the invention, the addition of the fieldreplaceable packaged refrigeration module (660 in FIG. 6) to athermosyphon (690 in FIG. 6) serves to create a system wherein thethermosyphon is used to passively cool the heat source (62 in FIG. 6)and the field replaceable packaged refrigeration module is used tolower, or maintain, the base temperature of the thermosyphon.Consequently, the field replaceable packaged refrigeration module can beoperated intermittently, on an as needed basis, to minimize the powerused by the system and to minimize the wear and tear of the movingparts. The net result is the ability to manage and remove heat from theheat source while saving energy since the field replaceable packagedrefrigeration module does not need to operate at all times. In anotherembodiment, the field replaceable packaged refrigeration module ispositioned directly over the main heat source, such as a CPU, while thethermosyphon is used for smaller heat sources or secondary cooling.Consequently, the use of a thermosyphon with the field replaceablepackaged refrigeration module allows for more cooling capability andmore efficient cooling, lowered load on the field replaceable packagedrefrigeration module, and a lower failure rate of the cooling system andits moving parts.

[0027] The present invention can be utilized in existing electronicsystems and unlike prior art liquid-based cooling systems, the variousparts of the field replaceable packaged refrigeration module withthermosyphon of the invention, including the very minimal tubing (694and 696 in FIG. 6), are largely self-contained in the field replaceablepackaged refrigeration module with thermosyphon. Therefore a failure ofany of the tubes would typically not result in the introduction ofliquid into, or onto, the electronic devices and would not causecatastrophic system failure, as was the risk with prior art liquid-basedcooling systems.

[0028] In one embodiment of the invention, a single thermosyphon iscoupled to a single field replaceable packaged refrigeration module as aunit. In other embodiments of the invention, multiple thermosyphons arecoupled to, and serviced by a single field replaceable packagedrefrigeration module mounted in a central location. In this way, singleor multiple heat sources can be serviced by a single field replaceablepackaged refrigeration module.

[0029] The field replaceable packaged refrigeration module withthermosyphon of the present invention is a modified liquid-based coolingsystem and therefore provides the cooling capacity of a prior artliquid-based cooling systems. However, unlike prior art liquid-basedcooling systems, the field replaceable packaged refrigeration modulewith thermosyphon of the invention is modular and self-contained and istherefore field and/or customer replaceable with minimal effort usingstandard tools. In addition, unlike prior art liquid-based coolingsystem, the field replaceable packaged refrigeration module withthermosyphon of the invention, in one embodiment, uses the passive, aircooled, and low energy thermosyphon to perform the majority of thecooling, while providing the added cooling capacity of a liquid-basedcooling system in the form of the intermittently operating fieldreplaceable packaged refrigeration module.

[0030] In addition, unlike prior art liquid-based cooling systems, thefield replaceable packaged refrigeration module with thermosyphon of theinvention is compact and simple in both operation and installation, withminimal parts to fail or break and minimal added complexity. Therefore,unlike prior art liquid-based cooling systems, the field replaceablepackaged refrigeration module with thermosyphon of the invention issturdy and reliable.

[0031] In addition, the field replaceable packaged refrigeration moduleportion of the present invention is specifically designed to beoperational in any orientation. Consequently, unlike prior artliquid-based cooling systems, the field replaceable packagedrefrigeration module portion of the present invention can be mounted,and operated, at any angle. This makes the field replaceable packagedrefrigeration module with thermosyphon of the present inventionparticularly well suited for use with electronic systems.

[0032]FIG. 1 is a functional diagram of a field replaceable packagedrefrigeration module 10 designed according to one embodiment of theinvention. Referring to FIG. 1, field replaceable packaged refrigerationmodule 10 includes a compressor 12, a condenser 14, an optional receiver16, an expansion device 18 and an evaporator 20, all of which areconnected together in refrigeration loop 22 through which a refrigerant,such as R134A, is circulated.

[0033] As also shown in FIG. 1, compressor 12, condenser 14, optionalreceiver 16, expansion device 18 and evaporator 20, in a refrigerationloop 22 are self-contained in field replaceable packaged refrigerationmodule 10, as indicated by dashed line 11.

[0034] In one embodiment of the invention, evaporator 20 is positionedin thermal contact with a heat source 24, such as an electroniccomponent, or the base of a thermosyphon, as discussed below, which isto be cooled. As is well understood by those of ordinary skill in theart, compressor 12 compresses the refrigerant (not shown) into ahigh-pressure, high temperature liquid that is then conveyed tocondenser 14. At condenser 14, the refrigerant is allowed to cool beforebeing conveyed to receiver 16. From receiver 16, the refrigerant passesthrough expansion device 18, which may be, for example, a capillarytube, and into evaporator 20. The liquid refrigerant evaporates inevaporator 20 and in the process absorbs heat from heat source 24 toproduce the desired cooling effect. From evaporator 20 the refrigerantis drawn back into compressor 12 to begin another cycle throughrefrigeration loop 22.

[0035] In accordance with the present invention, compressor 12 is one ofseveral new generation compressors that are relatively small, on theorder of 2.0 inches in diameter and 3 to 4 inches long. In oneembodiment of the invention, compressor 12 is less than 1.7 inches indiameter and less than 4 inches long. One example of this new generationof compressors is the relatively new linear compressor now being used inthe more standard refrigeration, i.e., non-electronics, industry. In oneembodiment of the invention, compressor 12 is a linear compressor whoseoperation is controlled by drive circuit 26.

[0036] As discussed in more detail with respect to FIG. 2, a linearcompressor is a positive displacement compressor having one or more freefloating pistons that are driven directly by a linear motor. Thus, alinear compressor differs from a conventional reciprocating and rotarycompressor where the pistons are driven through a crankshaft linkage, orby a rotary motor through a mechanical linkage, respectively. Since thecapacity of any compressor is directly related to the size anddisplacement of the pistons, a linear compressor can typically be madesmaller than a crankshaft reciprocating or rotary compressor but canmaintain the same capacity since the displacement of the pistons is notdependent on the size of a mechanical linkage. In addition, since alinear compressor usually comprises fewer moving parts than a crankshaftreciprocating or rotary compressor, the linear compressor is typicallyquieter than a crankshaft reciprocating or rotary compressor.Furthermore, since the pistons of a double-piston linear compressor movein opposition to one another, the reaction forces of the pistons willcancel each other out and the vibrations that are commonly experiencedwith crankshaft reciprocating or rotary compressors will consequently besuppressed. Consequently, linear compressors offer many advantages overa crankshaft reciprocating compressor or a rotary compressor forapplication as compressor 12 in field replaceable packaged refrigerationmodule 10.

[0037] The linear compressors suitable for use as compressor 12 in fieldreplaceable packaged refrigeration module 10 can be any of a variety ofsingle, double or multiple-piston linear compressors that are known inthe art. For example, in one embodiment of the invention, linearcompressor 12 is a single-piston linear compressor of the type disclosedin U.S. Pat. No. 5,993,178, which is hereby incorporated herein byreference, or a double-piston linear compressor of the type disclosed inU.S. Pat. No. 6,089,836 or U.S. Pat. No. 6,398,523, all of which arehereby incorporated herein by reference.

[0038] Referring to FIG. 2, an exemplary linear compressor 120, suitablefor use as compressor 12 in FIG. 1, comprises a housing 28, first andsecond cylinders 30, 32 which are connected to, or formed integrallywith, housing 28, and first and second pistons 34, 36 which are slidablyreceived within first and second cylinders 30, 32, respectively. Theends of housing 28 are, in one embodiment, hermetically sealed, such asby end plates 38. In addition, each cylinder 30, 32 has an axialcenterline CL that is, in one embodiment, coaxial with that of the othercylinder. Furthermore, housing 28 is, in one embodiment, constructed ofa magnetically permeable material, such as stainless steel, and pistons34, 36 are optimally constructed of a magnetically indifferent material,such as plastic or ceramic.

[0039] In the embodiment of exemplary linear compressor 120 shown inFIG. 2, each piston 34, 36 is driven within its respective cylinder 30,32 by linear motor 40. Each motor 40 includes a ring-shaped permanentmagnet 42 and an associated electrical coil 44. In the embodiment of anexemplary linear compressor 120 shown in FIG. 2, magnet 42 is mountedwithin housing 28 and coil 44 is wound upon a portion of piston 34, 36.In one embodiment, magnet 42 is radially charged, and each motor 40includes a cylindrical core 46 mounted within housing 28 adjacent magnet42 to direct the flux lines (not shown) from magnet 42 across coil 44.In one embodiment, coil 44 is energized by an AC current, from drivecircuit 26 (FIG. 1), over a corresponding lead wire (not shown). In oneembodiment of the invention, drive circuit 26 is programmed such that,when the AC current is applied to coils 44 (FIG. 2), pistons 34, 36 willreciprocate toward and away from each other along the axial centerlineCL of cylinders 30, 32. In another embodiment, DC current is applied. Inone embodiment, spring 48, or similar means, may be connected betweeneach piston 34, 36 and adjacent end plate 38 to aid in matching thenatural frequency of piston 34, 36 to the frequency of the current fromdrive circuit 26 (FIG. 1).

[0040] The embodiment of an exemplary linear compressor 120 shown inFIG. 2 also includes a compression chamber 50 located within cylinders30, 32, between pistons 34, 36. During the expansion portion of eachoperating cycle of linear compressor 120, motors 40 will move pistons34, 36 away from each other. This will cause the then gaseousrefrigerant within evaporator 20 (FIG. 1) to be drawn into compressionchamber 50 (FIG. 2), through an inlet port 52 in housing 28. During thesuccessive compression portion of the operating cycle of exemplarylinear compressor 120, motors 40 will move pistons 34, 36 toward eachother. Pistons 34, 36 will consequently compress the then gaseousrefrigerant within compression chamber 50 into a liquid and eject itinto condenser 14 (FIG. 1), through an outlet port 54 (FIG. 2) inhousing 28. In one embodiment, suitable check valves 56, 58 are providedin inlet and outlet ports 52, 54, respectively, to control the flow ofrefrigerant through inlet and outlet ports 52, 54 during the expansionand compression portions of each operating cycle.

[0041] While a specific embodiment of a field replaceable packagedrefrigeration module 10 is discussed above that includes exemplarylinear compressor 120, those of skill in the art will recognize that thechoice of a linear compressor, or any particular compressor, for use ascompressor 12 in the discussion above was made for illustrationsimplicity and to avoid detracting from the invention by describingmultiple specific embodiments at one time. In other embodiments of theinvention appropriately sized rotary compressor, or other type ofcompressor, can be used as compressor 12. For instance, in variousembodiments of the invention, compressor 12 can be: a reciprocatingcompressor; a Swash-plate compressor; a rolling piston compressor; ascroll compressor; a rotary vane compressor; a screw compressor; anaerodynamic-turbo compressor; an aerodynamic-axial compressor; or anyother reciprocating, volumetric or aerodynamic compressor known in theart, or developed after this application is filed. Consequently, thepresent invention should not be read as being limited the particularembodiments discussed above using linear, or any specific, compressortypes.

[0042] Consequently, the present invention should not be read as beinglimited the particular embodiments discussed above using linear, or anyspecific, compressor types.

[0043] In one embodiment of the invention, a single thermosyphon (690 inFIG. 6) is coupled to a single field replaceable packaged refrigerationmodule 10 as a unit. In other embodiments of the invention, multiplethermosyphons (690 in FIG. 6) are coupled to, and serviced by a singlefield replaceable packaged refrigeration module 10 mounted in a centrallocation. In this way, single or multiple heat sources can be servicedby a single field replaceable packaged refrigeration module. Inaddition, according to the principles of the invention, fieldreplaceable packaged refrigeration module 10 can be readily adapted foruse in cooling one or more integrated circuits that are mounted on asingle circuit board and are part of a larger electronic system. Forexample, in many computer servers a number of integrated circuits aremounted on a single circuit board that, in turn, is housed within anenclosure/cabinet or “rack unit”, and a number of such rack units are,in turn, mounted in corresponding racks that are supported in thehousing of the server.

[0044] In accordance with one industry standard, each rack unit has aheight of only 1.75 inches. This fact makes use of prior artliquid-based cooling systems extremely difficult, if not impossible, andmakes the extensive, and potentially disastrous, plumbing, discussedabove, a system requirement. In contrast, a single, or even multiple,field replaceable packaged refrigeration modules 10, designed accordingto the principles of the invention, can be positioned within the housingof the server, and/or on the rack units, to directly cool the integratedcircuits that are located within or on the rack units or to provideadditional cooling for thermosyphons (690 in FIG. 6) cooling theintegrated circuits that are located within or on the rack units.Consequently, in one embodiment of the invention, field replaceablepackaged refrigeration modules 10, designed according to the invention,are housed within a small scale-cooling unit that can be located withineach rack unit and connected directly to cool each integrated circuit orthermosyphon as needed.

[0045] One example of a physical implementation of the functionaldiagram of a field replaceable packaged refrigeration module 10 of FIG.1 is shown as field replaceable packaged refrigeration module 60 of FIG.3, FIG. 4 and FIG. 5. As shown in FIGS. 3 and 4, according to oneembodiment of the invention, field replaceable packaged refrigerationmodule 60 is positioned adjacent an integrated circuit 62 that ismounted on a circuit board 64 or a thermosyphon (690 in FIG. 6) mountedon integrated circuit 62 on a circuit board 64. As discussed above, inaccordance with one embodiment of the invention, field replaceablepackaged refrigeration module 60 is sized such that, when positioned asshown in FIG. 4, field replaceable packaged refrigeration module 60 willfit within a rack unit of a conventional computer server or atelecommunications rack. In one embodiment of the invention, fieldreplaceable packaged refrigeration module 60 has a length 301 (FIG. 3)of approximately 6 inches, a width 303 of approximately 4 inches, and aheight 305 of approximately 1.75 inches. In another embodiment of theinvention, field replaceable packaged refrigeration module 60 has alength 301 of approximately 5 inches, a width 303 of approximately 4inches, and a height 305 of approximately 1.75 inches. Of course, thoseof skill in the art will recognize that length 301, width 303 and height305 of field replaceable packaged refrigeration module 60 can be variedto meet the needs of specific applications.

[0046] As shown in FIG. 3, in one embodiment of the invention, fieldreplaceable packaged refrigeration module 60 includes a housing 66 whichhas generally open front and back sides 68, 70, a conventionalair-cooled condenser 14, which is mounted within housing 66 between openfront and back sides 68, 70, a compressor 12 which is connected tohousing 66 by a suitable bracket 72, and an evaporator 20 which isconnected to housing 66, below condenser 14. As discussed above, in oneembodiment of the invention, compressor 12 is a linear compressor drivenby a drive circuit (not shown) in a manner similar to that discussedabove. In one embodiment of the invention, evaporator 20 is aconventional cold plate-type evaporator that is thermally coupled to thetop of integrated circuit 62 (FIG. 4) by either custom or conventionalmeans. As discussed in more detail below, in another embodiment of theinvention, field replaceable packaged refrigeration module 60 is coupledto the evaporator (620 in FIG. 6) of a thermosyphon (690 in FIG. 6) byeither custom or conventional means. In one embodiment of the invention,condenser 14 is cooled by a flow of air from a system fan (not shown)that is mounted in the housing (not shown) of the server (not shown). Inaddition, in one embodiment of the invention, field replaceable packagedrefrigeration module 60 is connected to circuit board 64 with a numberof standoffs 74 and screws 76.

[0047] During the normal operation of field replaceable packagedrefrigeration module 60, relatively high-pressure liquid refrigerantfrom compressor 12 is conveyed through a conduit 76 to condenser 14. Inone embodiment of the invention, the high-pressure liquid refrigerant iscooled in condenser 14 by the flow of air from a system fan (not shown).The refrigerant is then conveyed through a capillary tube 78 toevaporator 20. The refrigerant evaporates in evaporator 20 and in theprocess absorbs heat from integrated circuit 62 to thereby coolintegrated circuit 62 (FIG. 4). The now gaseous refrigerant is thendrawn back into compressor 12 through conduit 80. This cycle is thenrepeated as required to produce a desired cooling effect for integratedcircuit 62.

[0048]FIG. 5 is a computer-generated representation of one embodiment offield replaceable packaged refrigeration module 60 of FIG. 3 and FIG. 4and therefore represents a computer-generated representation of aphysical implementation of the functional diagram of field replaceablepackaged refrigeration module 10 of FIG. 1. Shown in FIG. 5 are:condenser 14; compressor 12; evaporator 20; and tubing 501. It is worthnoting that tubing 501 is relatively minimal and, is therefore, asubstantial improvement over the extensive “plumbing” associated withprior art liquid-based cooling systems. Indeed, unlike prior artliquid-based cooling systems, the various parts of field replaceablepackaged refrigeration module 60 of the invention, including the veryminimal tubing 501, are self-contained in field replaceable packagedrefrigeration module 60 and therefore a failure of any of the tubes 501would typically not result in the introduction of liquid into or ontothe electronic devices (62 in FIG. 4) and would not cause thecatastrophic system failure that was the risk associated with prior artliquid-based cooling systems.

[0049] As noted above, it is highly desirable to provide a coolingsystem that uses minimal power and has a large thermal inertia. In theseapplications, a passive refrigeration sub-system is coupled with thefield replaceable packaged refrigeration module discussed above to yielda hybrid system that is more power efficient than the field replaceablepackaged refrigeration module used alone.

[0050]FIG. 6 is cross sectional view of one embodiment of a fieldreplaceable packaged refrigeration module with thermosyphon 600according to the principles of the present invention. As shown in FIG.6, according to one embodiment of the invention, field replaceablepackaged refrigeration module 660 is coupled by capillary tubing 694 toa cold plate evaporator 620 of a thermosyphon 690 positioned adjacent aheat source 62, such an integrated circuit or CPU. As discussed above,in accordance with one embodiment of the invention, field replaceablepackaged refrigeration module 660, and field replaceable packagedrefrigeration module with thermosyphon 600, is sized such that, whenpositioned as shown in FIG. 6, field replaceable packaged refrigerationmodule 660 will fit within a rack unit of a conventional computer serveror a telecommunications rack.

[0051] As shown in FIG. 6, in one embodiment of the invention, fieldreplaceable packaged refrigeration module 660 includes a conventionalair-cooled condenser 614 coupled to a compressor 612 by tubing 696. Asdiscussed above, in one embodiment of the invention, compressor 612 is alinear compressor driven by a drive circuit (not shown) in a mannersimilar to that discussed above. In one embodiment of the invention,condenser 614 is cooled by a flow of air from a system fan (not shown)that is mounted in the housing (not shown) of the server (not shown).

[0052] As also shown in FIG. 6, thermosyphon 690 includes a cold-plateevaporator 620. In one embodiment of the invention, cold-plateevaporator 620 is a conventional cold plate-type evaporator that isthermally coupled to the top of heat source 62 by conventional means. Asshown in FIG. 6, in one embodiment of the invention, thermosyphon 690also includes: an evaporator 691, holding a refrigerant or working fluid692 such as R134A, water or a dielectric coolant; thermosyphon condenser695 coupled to evaporator 691 by tubing 693.

[0053] In one embodiment of the invention, cold plate evaporator 620 ofthermosyphon 690 is coupled to field replaceable packaged refrigerationmodule 660 by capillary tubes 694. Thermosyphons, such as thermosyphon690, and their operation is well known in the art. Therefore, a detaileddescription of thermosyphon 690 is omitted here to avoid detracting fromthe invention.

[0054] The addition of the field replaceable packaged refrigerationmodule 660 to thermosyphon 690 serves to create a system 600 whereinthermosyphon 690 is used to passively cool heat source 62 and fieldreplaceable packaged refrigeration module 660 is used to lower, ormaintain, the base temperature of thermosyphon 690. Consequently, fieldreplaceable packaged refrigeration module 660 can be operatedintermittently, on an as needed basis, to minimize the power used byfield replaceable packaged refrigeration module with thermosyphon 600and to minimize the wear and tear of the moving parts. The net result isthe ability to manage and remove heat from heat source 62 while savingenergy since field replaceable packaged refrigeration module 660 doesnot need to operate at all times.

[0055] In one embodiment of the invention, a temperature sensor (notshown) is used to monitor the temperature of a component, such as coldplate evaporator 620 of thermosyphon 690 or a surface of heat source 62.In one embodiment of the invention, when a predetermined “maximum” basetemperature is exceeded, compressor 612 of field replaceable packagedrefrigeration module 660 is started, typically via a switch (not shown),and field replaceable packaged refrigeration module 660 operates untilthe base temperature of thermosyphon 690 is lowered to a predeterminedlevel. Consequently, the use of thermosyphon 690 with field replaceablepackaged refrigeration module 660 allows for more cooling capability andmore efficient cooling, lowered load on field replaceable packagedrefrigeration module 660, and a lower failure rate of field replaceablepackaged refrigeration module with thermosyphon 600 and its movingparts.

[0056] In another embodiment of the invention, heat source 62 is amicroprocessor whose activity is monitored by a monitoring deviceimplemented in hardware or software (not shown). In this embodiment ofthe invention, when a predetermined activity level for the processor isreached, compressor 612 of field replaceable packaged refrigerationmodule 660 is started, typically via a switch (not shown), and fieldreplaceable packaged refrigeration module 660 operates until theactivity level of the processor drops below a predetermined level.Consequently, in this embodiment of the invention, field replaceablepackaged refrigeration module with thermosyphon 600 tries to anticipatecooling needs and operates to provide the thermal reservoir to handleincreases in activity before the heat is produced. Therefore, thermalspikes, and potential thermal damage to the processor and itsperformance are avoided.

[0057] In one embodiment of the invention, a single thermosyphon 690 iscoupled to a single field replaceable packaged refrigeration module 660as a unit 600. In other embodiments of the invention, multiplethermosyphons 690 are coupled to, and serviced by, a single fieldreplaceable packaged refrigeration module 660 mounted in a centrallocation. In this way, single or multiple heat sources 62 can beserviced by a single field replaceable packaged refrigeration module.

[0058] As discussed above, the present invention is directed to a fieldand/or customer replaceable packaged refrigeration module withthermosyphon that is suitable for use in standard electronic componentenvironments. The field replaceable packaged refrigeration module withthermosyphon of the invention is largely self-contained and isspecifically designed to have physical dimensions similar to those of astandard air-based cooling system, such as a fined heat sink or heatpipe. As a result, the present invention can be utilized in existingelectronic systems without the need for board or rack/cabinetmodification or the “plumbing” associated with prior art liquid-basedcooling systems.

[0059] As also discussed above, the use of a field replaceable packagedrefrigeration module with a thermosyphon serves to lower the basetemperature of the thermosyphon and so allows intermittent operation ofthe field replaceable packaged refrigeration module. The net result isthe ability to manage and remove heat from the heat source while savingenergy since the field replaceable packaged refrigeration module doesnot need to operate at all times. Consequently, the use of athermosyphon with the field replaceable packaged refrigeration moduleallows for more efficient cooling, lowered load on the field replaceablepackaged refrigeration module, and a lower failure rate of the coolingsystem and its moving parts.

[0060] In addition, since the field replaceable packaged refrigerationmodule with thermosyphon of the invention is a modified liquid-basedcooling system, the field replaceable packaged refrigeration module withthermosyphon of the invention provides the cooling capacity of prior artliquid-based cooling systems. However, like prior art air-based coolingsystems, the field replaceable packaged refrigeration module withthermosyphon of the invention is modular and largely self-contained andis therefore field and/or customer replaceable with minimal effort usingstandard tools.

[0061] In addition, the field replaceable packaged refrigeration moduleused with the present invention is self contained and specificallydesigned to be operational in any orientation. Consequently, unlikeprior art liquid-based cooling systems, the field replaceable packagedrefrigeration module portion of the present invention can be mounted,and operated, at any angle. This makes the field replaceable packagedrefrigeration module with thermosyphon of the present inventionparticularly well suited for use with electronic systems.

[0062] As a result of the features of the present invention discussed indetail above, the field replaceable packaged refrigeration module withthermosyphon of the present invention provides the cooling capacity of aliquid-based cooling system and yet is modular, compact, simple indesign, and simple to use, like an air-based cooling system.Consequently, the field replaceable packaged refrigeration module withthermosyphon of the present invention can meet the cooling needs of thenext generation of electronic devices and systems and can make furtherspeed and device density improvements in microprocessor design aworkable possibility.

[0063] It should be recognized that, while the present invention hasbeen described in relation to the specific embodiments thereof discussedabove, those skilled in the art may develop a wide variation ofstructural and operational details without departing from the principlesof the invention.

[0064] As one example, the choice of a linear compressor, or anyparticular linear compressor, for use as compressor 612 in thediscussion above was made for illustration simplicity and to avoiddetracting from the invention by describing multiple specificembodiments at one time. In other embodiments of the invention,appropriately sized rotary compressors, or other compressors, can beused as compressor 612. For instance, in various embodiments of theinvention, compressor 612 can be: a reciprocating compressor; aswash-plate compressor; a rolling piston compressor; a scrollcompressor; a rotary vane compressor; a screw compressor; anaerodynamic-turbo compressor; an aerodynamic-axial compressor; or anyother reciprocating, volumetric or aerodynamic compressor known in theart, or developed after this application is filed. Consequently, thepresent invention should not be read as being limited the particularembodiments discussed above using linear, or any specific, compressortypes.

[0065] As another example, specific dimensions were discussed above asexamples of possible values for length 301, width 303 and height 305 offield replaceable packaged refrigeration module 60 or 660. Those ofskill in the art will recognize that length 301, width 303 and height305 of field replaceable packaged refrigeration module 60 or 660 can bevaried for specific applications and that the present invention shouldnot be read as being limited the particular embodiments discussed abovewith the particular dimensions discussed by way of illustration.

What is claimed is:
 1. A packaged refrigeration module with thermosyphon for cooling electronic components, said packaged refrigeration module with thermosyphon comprising: a packaged refrigeration module, said packaged refrigeration module comprising: a packaged refrigeration module housing; refrigerant; a compressor; a condenser; and an expansion device; wherein, said compressor, said condenser, and said expansion device are coupled together in a refrigeration loop within said packaged refrigeration module housing and said refrigerant is contained within said refrigeration loop such that said packaged refrigeration module is a self-contained module; and a thermosyphon, said thermosyphon being operatively coupled to said packaged refrigeration module refrigeration loop.
 2. The packaged refrigeration module with thermosyphon of claim 1; wherein, said packaged refrigeration module has a width of approximately 4 inches, a length of approximately 5 inches and a height of approximately 1.75 inches.
 3. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a single piston linear compressor.
 4. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a dual-piston linear compressor.
 5. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a multi-piston linear compressor.
 6. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a rotary compressor.
 7. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a reciprocating compressor.
 8. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a rolling piston compressor.
 9. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a rotary vane compressor.
 10. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a screw compressor.
 11. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a swash-plate compressor.
 12. The packaged refrigeration module with thermosyphon of claim 1; wherein, said compressor is a scroll compressor.
 13. A circuit board, said circuit board comprising: at least one electronic component; a packaged refrigeration module for cooling said electronic component, said packaged refrigeration module comprising: a packaged refrigeration module housing; refrigerant; a compressor; a condenser; an expansion device; wherein, said compressor, said condenser and said expansion device are coupled together in a refrigeration loop within said packaged refrigeration module housing and said refrigerant is contained within said refrigeration loop such that said packaged refrigeration module is a self-contained module; and a thermosyphon, said thermosyphon being operatively coupled to said packaged refrigeration module refrigeration loop; wherein, said thermosyphon includes a thermosyphon evaporator cold-plate, said thermosyphon evaporator cold-plate being mounted directly over a first surface of said electronic component.
 14. The circuit board of claim 13; wherein, said packaged refrigeration module has a width of approximately 4 inches, a length of approximately 5 inches and a height of approximately 1.75 inches
 15. The circuit board of claim 13; wherein, said compressor is a single piston linear compressor.
 16. The circuit board of claim 13; wherein, said compressor is a dual-piston linear compressor.
 17. The circuit board of claim 13; wherein, said compressor is a multi-piston linear compressor.
 18. The circuit board of claim 13; wherein, said compressor is a rotary compressor.
 19. The circuit board of claim 13; wherein, said compressor is a reciprocating compressor.
 20. The circuit board of claim 13; wherein, said compressor is a rolling piston compressor.
 21. The circuit board of claim 13; wherein, said compressor is a rotary vane compressor.
 22. The circuit board of claim 13; wherein, said compressor is a screw compressor.
 23. The circuit board of claim 13; wherein, said compressor is a swash-plate compressor.
 24. The circuit board of claim 13; wherein, said compressor is a scroll compressor.
 25. The circuit board of claim 13; wherein, said electronic component is an integrated circuit.
 26. The circuit board of claim 13; wherein, said electronic component is a microprocessor.
 27. An electronic system, said electronic system comprising: a rack unit, said rack unit comprising: at least one electronic component; a packaged refrigeration module, said packaged refrigeration module comprising: a packaged refrigeration module housing; refrigerant; a compressor; a condenser; an expansion device; wherein, said compressor, said condenser, and said expansion device are coupled together in a refrigeration loop within said packaged refrigeration module housing and said refrigerant is contained within said refrigeration loop such that said packaged refrigeration module is a self-contained module; and a thermosyphon, said thermosyphon being operatively coupled to said packaged refrigeration module refrigeration loop; wherein, said thermosyphon includes a thermosyphon evaporator cold-plate, said thermosyphon evaporator cold-plate mounted directly over a first surface of said electronic component.
 28. The electronic system of claim 27; wherein, said packaged refrigeration module has a width of approximately 4 inches, a length of approximately 5 inches and a height of approximately 1.75 inches.
 29. The electronic system of claim 27; wherein, said compressor is a single piston linear compressor.
 30. The electronic system of claim 27; wherein, said compressor is a dual-piston linear compressor.
 31. The electronic system of claim 27; wherein, said compressor is a multi-piston linear compressor.
 32. The electronic system of claim 27; wherein, said compressor is a rotary compressor.
 33. The electronic system of claim 27; wherein, said compressor is a reciprocating compressor.
 34. The electronic system of claim 27; wherein, said compressor is a rolling piston compressor.
 35. The electronic system of claim 27; wherein, said compressor is a rotary vane compressor.
 36. The electronic system of claim 27; wherein, said compressor is a screw compressor.
 37. The electronic system of claim 27; wherein, said compressor is a swash-plate compressor.
 38. The electronic system of claim 27; wherein, said compressor is a scroll compressor.
 39. The electronic system of claim 27; wherein, said electronic component is an integrated circuit.
 40. The electronic system of claim 27; wherein, said electronic component is a microprocessor. 